[1] Field of the Invention
The present invention relates to a mixer for mixing multiple materials and an agitator for agitating or pulverizing one or more types of materials.
[2] Related Art
In the manufacture of chemicals and food products, agitators are generally used for mixing more than one material or pulverizing particulate matter. Some proposed agitators include: ones with a structure in which an agitating screw is provided within a vessel where material such as liquid and powder is poured, and the material in the vessel is agitated by rotating the screw (e.g. Japanese Patent Publication No. 3072467); and ones with a structure in which a screw-free agitation vessel itself, with material contained therein, is rotated, and the rotation direction of the agitation vessel is inverted by reversing the rotation direction of the motor at regular time intervals (e.g. Japanese Laid-Open Patent Application Publication No. 2002-1084). The agitator proposed in the latter reference rotates the agitation vessel while switching the rotation direction in regular intervals, and thereby produces highly efficient agitation of its contained material.
This agitator, proposed in Japanese Laid-Open Patent Application Publication No. 2002-1084 above, does not experience much difficulty in switching the rotation direction of the agitation vessel, which is achieved by switching the rotation direction of the drive source, such as a motor, between forward and reverse, if the agitation vessel and material contained therein have small masses.
In the case when the agitation vessel and contained material have rather large weights, however, inverting the rotation direction of the agitation vessel requires a substantial amount of energy, causing great energy loss, and also results in adding great loads to the motor of the drive source.